Most men with prostate cancers that are carefully monitored are unlikely to die of the disease, a new study shows.

One in seven men will be diagnosed with prostate cancer at some point in their lives.

Determining which prostate cancer patients should be treated with surgery and/or radiation is often a difficult decision. The treatments carry serious side effects, including impotence and incontinence.

Researchers at Johns Hopkins Medicine analyzed survival statistics of more than 1,200 prostate cancer patients undergoing so-called “watchful waiting” or “active surveillance.” None had surgery or radiation, but only two died. Three others developed metastatic disease, meaning their cancer had spread.

This means less than one-half of 1 percent of the men had adverse outcomes even though they had no treatment other than to monitor their cancer.

"Our study should reassure men that carefully selected patients enrolled in active surveillance programs for their low-risk prostate cancers are not likely to be harmed by their disease," says H. Ballentine Carter, M.D., professor and director of adult urology there.

The study was reported in the Journal of Clinical Oncology.